Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
  • B05D5/005—Repairing damaged coatings
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
  • B05D3/06—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation
  • B05D3/061—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation using U.V.
  • B05D3/065—After-treatment
  • B05D3/067—Curing or cross-linking the coating

Definitions

• the invention relates to a method for producing a multilayer Refinishing, which is used in particular in the field of Vehicle and vehicle parts painting.
• the method is particularly suitable for Repair of body parts and smaller damaged areas.
• a drying or hardening of the painted Vehicles or vehicle parts can either be at room temperature overnight or in shorter time due to forced drying or hardening, for example 30 minutes at 60 ° C in a cabin.
• forced drying or hardening for example 30 minutes at 60 ° C in a cabin.
• IR radiators are usually used to prevent drying accelerate.
• the procedure is, for example, that wet-wet on a basecoat after a short flash off, a clear coat is applied and both layers cured within 20-25 minutes using one or more IR radiators become. Especially for the refinishing of body parts and smaller ones Damage points exist for reasons of effectiveness, the necessary To further shorten drying or curing times.
• DE-A-15 71 175 describes a method for curing an air-drying unsaturated polyester resin layer described, which in the wood coating Application. The curing takes place here with flashes of light from an electrical gas-filled flash tube.
• DE-A-41 33 290 describes a method for producing a Multi-layer coating for automotive serial painting described, in which a radiation-curable coating agent is used as the clear lacquer and the Application of the coating agent when illuminated with light of a wavelength of over 550 nm or in the absence of light and curing by means of high-energy radiation is carried out.
• the clear coat is applied to a KTL primer, filler and basecoat coated and at 120-140 ° C baked substrate applied and then irradiated.
• EP-A-0 000 407 describes a radiation-curable coating agent Basis of an OH-functional polyester resin esterified with acrylic acid, one Vinyl compound, a photoinitiator and a polyisocyanate.
• a first Radiation curing takes place using UV light and in a second curing step
• the OH / NCO crosslinking gives the coating its final hardness.
• the second hardening step can take place at 130-200 ° C or over several days Room temperature.
• the object of the invention was to provide a method for producing a multilayer Refinishing, in particular for refinishing vehicle parts and to repair smaller damaged areas, which the Previously usual drying times reduced and coatings, which despite shortened Drying times without sacrificing quality meet the requirements of a Refinishing, especially with regard to hardness, scratch resistance and elasticity will be sufficient.
• the one for hardening the transparent clear lacquer layer or the pigmented one High-energy pulsed UV radiation to be used with a topcoat Radiation source which is a high energy electron flash device, in the following high-energy UV flash lamp or simply UV flash lamp called, acts. With this radiation source it is possible to cover the in the Cure completely in seconds.
• the multilayer structures obtained by the process according to the invention do the same for show a property level required for refinishing, as under usual repair conditions dried or hardened multi-layer coatings.
• a primer is applied if necessary and / or filler precoated substrate with a basecoat and wet-on-wet, if necessary after a short flash-off, a clear coat is applied. Then be both layers at room temperature overnight or within 20-80 min 40-80 ° C hardened.
• the applied Basecoat is preferably only dried briefly and then the clearcoat is applied and subjected to radiation.
• the radiation curing of the clear coat or the pigmented top coat takes place According to the invention with pulsed high-energy UV radiation.
• a radiation source one or more UV flash lamps are used for this purpose.
• the UV flash lamps emit light of a wavelength of 200-900 nm with a maximum at 500 nm.
• the flashes can be triggered approximately every 4 s, for example.
• the UV flash lamps preferably contain a plurality of flash tubes, for example with inert gas, such as xenon, filled quartz tubes.
• the UV flash lamps are said to be on the Surface of the coating to be cured an illuminance of at least 10 Megalux, preferably from 10-80 Megalux per flash discharge.
• the electrical Power per flash discharge should preferably be 1-10 kJoules.
• With the UV flash lamp it is preferably a transportable device that directly can be positioned in front of the damaged area to be repaired. Usable UV flash lamps are described, for example, in WO-A-9411123 and in EP-A-0
• UV flash lamps are commercially available.
• the transparent clearcoats or pigmented top coats are radiation-curable coating agents that crosslink only via radical and / or cationic polymerization.
• These can be aqueous systems with high solids content, which are used as an emulsion are present, but the systems can also be in solvent-containing form. However, it is preferably 100% lacquer systems that do not contain solvents and can be applied without water.
• All radiation-curable binders can be used in the process of the invention usual radiation-curable binders or mixtures thereof are used, which are known to the person skilled in the art and are described in the literature. It is about either to be crosslinkable by radical polymerization or by cationic Polymerization crosslinkable binders. In the former arise through action from high-energy radiation to the binder or coating agent radicals that then trigger the crosslinking reaction. With the cationic curing systems are formed by irradiation from initiators Lewis acids, which then Trigger crosslinking reaction.
• the free-radically curing binders can e.g. to prepolymers like Poly- or oligomers that contain olefinic double bonds in the molecule, act.
• prepolymers or oligomers are (meth) acrylic functional (Meth) acrylic copolymers, epoxy resin (meth) acrylates, polyester (meth) acrylates, Polyether (meth) acrylates, polyurethane (meth) acrylates, unsaturated polyesters, Amino (meth) acrylates, melamine (meth) acrylates, unsaturated polyurethanes or Silicone (meth) acrylates.
• the molecular weight (Mn) of these compounds is preferably from 200 to 10,000.
• Aliphatic and / or cycloaliphatic (meth) acrylates used are particularly preferred (cyclo) aliphatic polyurethane (meth) acrylates and polyester (meth) acrylates.
• the Binders can be used individually or in a mixture.
• the prepolymers can optionally be used in so-called reactive diluents, i.e. reactive liquid monomers, dissolved.
• the reactive thinners are in generally in amounts of 1-50 wt .-%, preferably 5-30 wt .-%, based on the Total weight of prepolymer and reactive thinner used.
• the Reactive diluents can be mono-, di- or poly-unsaturated. Examples for monounsaturated reactive diluents are: (meth) acrylic acid and its esters, Maleic acid and its half esters, vinyl acetate, vinyl ether, substituted Vinyl ureas, styrene, vinyl toluene.
• unsaturated reactive diluents are: di (meth) acrylates such as alkylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, vinyl (meth) acrylate, Allyl (meth) acrylate, divinylbenzene, dipropylene glycol di (meth) acrylate, hexanediol di (meth) acrylate.
• di (meth) acrylates such as alkylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, vinyl (meth) acrylate, Allyl (meth) acrylate, divinylbenzene, dipropylene glycol di (meth) acrylate, hexanediol di (meth) acrylate.
• polyunsaturated reactive diluents are: glycerol tri (meth) acrylate, Trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, Pentaerythritol tetra (meth) acrylate.
• the reactive diluents can be used individually or in Mixture can be used.
• Preferred reactive diluents are diacrylates such as e.g. Dipropylene glycol diacrylate, tripropylene glycol diacrylate and / or Hexanediol diacrylate used.
• the free-radically curable coating agents contain photoinitiators.
• suitable Photoinitiators are, for example, those in the wavelength range from 190 to Absorb 400 nm.
• initiators for radical polymerization are chlorine-containing aromatic compounds, e.g. described in US-A-4 089 815, aromatic ketones as described in EP-A-0 003 002 and EP-A-0 161 463, Hydroxyalkylphenones as described in US-A-4,347,111.
• Alkyl or arylphosphine oxides hydroxyacetophenone derivatives and Benzophenone derivatives.
• the photoinitiators can be used, for example, in amounts of 0.1-5 wt .-%, preferably 0.5-3 wt .-%, based on the sum of radical polymerizable prepolymers, reactive diluents and initiators added become. They can be used individually or as mixtures.
• Binders known to those skilled in the art and described in the literature are used become. These can be, for example, polyfunctional epoxy oligomers which contain more than two epoxy groups in the molecule. It is convenient if the binders are free from aromatic structures. Such epoxy oligomers are described for example in DE-A-36 15 790.
• polyalkylene glycol diglycidyl ether hydrogenated bisphenol A glycidyl ether, Epoxy urethane resins, glycerol triglycidyl ether, diglycidyl hexahydrophthalate, Diglycidyl esters of dimer acids, epoxidized derivatives of (meth) cyclohexene, such as e.g. 3,4-epoxycyclohexyl-methyl (3,4-epoxycyclohexane) carboxylate or epoxidized Polybutadiene.
• the number average molecular weight of the polyepoxide compounds is preferably below 10,000.
• Reactive diluents such as e.g. Cyclohexene oxide, butene oxide, butanediol diglycidyl ether or Hexanediol diglycidyl ether can be used.
• Photoinitiators for cationic curing systems are substances that act as onium salts are known which photolytically release Lewis acids under the action of radiation. Examples include diazonium salts, sulfonium salts or iodonium salts. Triarylsulfonium salts are preferred.
• the photonitiators can be used in quantities of 0.5 to 5 wt .-%, based on the sum of cationically polymerizable Prepolymers, reactive diluents and initiators, individually or as a mixture be used.
• the transparent clearcoats and pigmented top coats can contain additives.
• the additives are are the usual additives that can be used in the paint sector.
• Additives are leveling agents, e.g. based on (meth) acrylic homopolymers or silicone oils, rheology influencing agents, such as finely divided silica or polymeric urea compounds, thickeners, such as crosslinked polycarboxylic acid or Polyurethanes, anti-foaming agents, wetting and elasticizing agents.
• leveling agents e.g. based on (meth) acrylic homopolymers or silicone oils
• rheology influencing agents such as finely divided silica or polymeric urea compounds
• thickeners such as crosslinked polycarboxylic acid or Polyurethanes
• anti-foaming agents wetting and elasticizing agents.
• light stabilizers are phenyl salicylates, Benzotriazole and derivatives, HALS compounds and oxalanilide derivatives.
• the transparent clearcoats and pigmented top coats can contain organic solvents and / or water.
• the solvents are common paint solvents. This can come from the manufacture of the binders or are sold separately added. Examples of such solvents are monohydric or polyhydric alcohols, e.g. Propanol, butanol, hexanol; Glycol ethers or esters, e.g. diethylene, Dipropylene glycol dialkyl ether, each with C1 to C6 alkyl, Ethoxypropanol, butyl glycol; Glycols, e.g. Ethylene glycol, propylene glycol and their oligomers, N-methylpyrrolidone and ketones, e.g.
• the clear lacquers which can be used according to the invention can comprise transparent pigments, such as e.g. Silicon dioxide, and possibly contain soluble dyes.
• the invention usable pigmented topcoats contain color and / or effect Pigments.
• pigments all common pigments are organic or suitable of inorganic nature. Examples of inorganic or organic Color pigments are titanium dioxide, micronized titanium dioxide, iron oxide pigments, carbon black, Azo pigments, phthalocyanine pigments, quinacridone and pyrrolopyrrole pigments. Examples of effect pigments are metal pigments, e.g. Aluminum pigments, and pearlescent pigments.
• radical curing systems various cationic curing systems or radical and cationic curing systems can be combined. Radically curing systems are preferably used.
• the radiation-curable coating agents can, in a known manner, for example, by spray application.
• the transparent Clearcoats can be applied to conventional aqueous or solvent-based basecoats be applied.
• Basecoats containing binders can be used.
• the basecoats included organic and / or inorganic color and / or effect pigments and / or Fillers, water and / or organic solvents and, if necessary, additives common in paint.
• the basecoats are applied to substrates that are coated with conventional primers, Filler and intermediate layers, such as those for multi-layer painting on the Motor vehicle sector can be used, can be pre-coated.
• preferred Substrates are metal or plastic parts.
• the drying or hardening of the basecoat film can take place at room temperature or at elevated temperature. Drying can preferably take place within a few Minutes, e.g. 3-10 minutes, at 40-80 ° C. This is particularly preferably done Drying the basecoat using infrared radiation. The IR drying can for example within 3-6 minutes.
• the clearcoat is applied, preferably in a resulting dry film layer thickness of 20-80 ⁇ m, preferred from 20-50 ⁇ m.
• a pigmented topcoat is used as a radiation-curable coating agent, for example, this can be applied to conventional solvent- or water-based fillers, Primers or intermediate layers can be applied. The pens-, Primer or intermediate layers can already be cured or be pre-dried.
• the clearcoat is preferred in multi-layer refinishing radiation-curable coating agent formulated.
• the Crosslinking using UV radiation After applying the clear coat or the pigmented top coat, the Crosslinking using UV radiation. They already serve as the UV radiation source described UV flash lamps.
• the coatings can be dried or hardened by a plurality of successive lightning discharges. Prefers 1 to 40 successive lightning discharges are triggered.
• the distance of the UV flash lamp to the substrate surface to be irradiated can be 5-50 cm, preferably 10-25 cm, particularly preferably 15-20 cm. Shielding the UV lamps to avoid radiation leakage can e.g. by Use of an appropriately lined protective housing around the transportable Lamp unit or with the help of other, known to those skilled in the art Security measures.
• the total irradiation time is in the range of a few seconds, for example in the range from 1 millisecond to 400 seconds, preferably from 4-160 seconds, each according to the number of selected lightning discharges.
• the Clear varnish shows very good adhesion to the basecoat and very good resistance to dissolving compared to the basecoat.
• the covers meet the requirements of one Refinish paint construction in the field of vehicle painting.
• the drying or The coatings, in particular the basecoat / clearcoat structure are hardened in Compared to repair lacquer structures dried or hardened in the usual way in an extremely short time. For example, it is possible to or curing process, including predrying the basecoat, within 5-15 Minutes, preferably 5-10 minutes.
• the process according to the invention is particularly suitable for refinishing smaller body parts or smaller damaged areas, but can also Refinishing of larger parts, for example larger vehicle parts be used.
• the pendulum damping test was carried out in accordance with DIN 53157 (according to König).
• the Erichsen deepening was carried out according to ISO 1520.
• UV curing was carried out using a UV flash lamp (3500 Ws) with 10 exposures (approx. 40 s) with an object distance of 20 cm.
• the coating technology properties of the coatings thus obtained are as above shown in Tables 1 and 2.
• the coatings are sufficient in terms of hardness, Scratch resistance and elasticity essentially meet the requirements of a Repair multi-coat paint can be provided.

Landscapes

• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Plasma & Fusion (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Paints Or Removers (AREA)
• Circuit Arrangement For Electric Light Sources In General (AREA)
• Discharge Lamp (AREA)
• Discharge-Lamp Control Circuits And Pulse- Feed Circuits (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=7804328

Family Applications (1)

Country Status (10)

Families Citing this family (27)

Family Cites Families (22)

• 1996
  • 1996-08-31 DE DE19635447A patent/DE19635447C1/de not_active Expired - Lifetime
• 1997
  • 1997-08-25 AU AU35278/97A patent/AU3527897A/en not_active Abandoned
  • 1997-08-26 EP EP97114719A patent/EP0826431B1/de not_active Expired - Lifetime
  • 1997-08-26 DK DK97114719T patent/DK0826431T3/da active
  • 1997-08-26 DE DE59709894T patent/DE59709894D1/de not_active Expired - Lifetime
  • 1997-08-26 PT PT97114719T patent/PT826431E/pt unknown
  • 1997-08-26 AT AT97114719T patent/ATE238107T1/de not_active IP Right Cessation
  • 1997-08-26 ES ES97114719T patent/ES2191795T3/es not_active Expired - Lifetime
  • 1997-08-29 JP JP9233891A patent/JPH1085660A/ja active Pending
  • 1997-08-29 CA CA002214281A patent/CA2214281A1/en not_active Abandoned
  • 1997-08-29 US US08/920,429 patent/US5932282A/en not_active Expired - Fee Related

Also Published As

Similar Documents

Legal Events